Improvement in corrugated spiral car-springs



C. FRENCH:

Car Spring.

N0. v34.952. Patented Apr. 15,1862.

inventor:

Witnesses= UNITED STATES PATENT OFFICE.

CARLOS FRENCH, OF SEYMOUR, CONNECTICUT.

IMPROVEMENT IN CORRUGATED SPIRAL CAR-SPRINGS.

Specification forming part of Letters Patent No. 34,952, dated April 15, 1862.

To all whom it may concern.-

Be it known that I, CARLOS FRENCH, of Seymour, in the county of New Haven and State of Connecticut, have invented certain new and useful Improvements in Car and Carriage Springs; and I do hereby declare the following to be a full, clear, and exact description of the same, reference being bad to the accompanying drawings, making a part of this specification, in which Figure 1 represents a perspective View of one of the springs complete. Fig. 2 represents a vertical section through the same. Fig. 3 represents a portion of the steel plate (of which the spring is composed) as it appears before being wound on the mandrel or former.

I am aware that corrugated springs of a flat or semi-elliptic form have been made; and I am also aware that springs have been made of a spirally-wound flat steel plate. These things I lay no claim to.

My invention consists in making a spiral or volute spring from a corrugated steel plate. the corrugations running in the direction of the winding of the plate and so that the load which the spring is to carry shall be at right angles, or thereabout, to the line of corrugations.

To enable others skilled in the art to make and use my invention, I will proceed to de scribe the same with reference to the drawings.

I take a steel plate A, Fig. 3, of proper width and thickness for the load the spring is to carry, and having formed corrugations a a a in it I proceed to wind it upon a mandrel or former that will give it the appear ance or form of that shown in Fig. 1, the coils 1 2 3 4, &c., receding from each other until the plate is all wound into a spiral form. That the base b of the coil or spring may be squared up properly to give it a permanent support, a portion, as shown by the red lines o d of Fig. 3, must be cut oif either before or after the spring is coiled. This gives the spring a firm base. The load or weight of the car or carriage comes upon the spring in a vertical line. The corrugations are horizontal, or

nearly so, and give to the spring the same I strength that it would have if the plate were of the thickness of the distance from out to out of the corrugated lines, while it has much less weight than such a plate. I therefore get a spring out of light metal that has all the strength of one made of a thicker plate as heretofore made, and thus producea spring of great value and utility.

I do not claim the corrugatin g of steel plates. nor do I claim a coiled o'r spiral spring wound from a steel plate; but

What I do claim, and desire to secure by Letters Patent, is

A car or carriage spring wound into a spiral form and havingcorrugations running in the direction of the spiral, said corrugations being formed in the plate in advance of the winding, by which means I produce a much lighter spring Without detracting from its strength, substantially as described.

CARLOS FRENCH. \Vitnesses:

A. B. STOUGHTON, H. W. PRICE. 

